Several applications are known in which connections need to be provided underwater, such as electrical connections and/or optical connections. Examples include a subsea installation for the production of hydrocarbons from a subsea well, in which different components of the subsea installation may need to be connected for power transfer and/or data communication. Such connections may for example comprise a connection from a topside installation, such as a floating or fixed platform, or from an onshore site, to a subsea component, for example by means of an umbilical or a subsea cable. Other connections include electrical connections between different type of subsea equipment, such as a connection between a subsea transformer and subsea switchgear, a data connection between different control modules or between a hub and a satellite well. In some configurations, a data connection may need to be provided over increased distances, for example between two subsea wells that are more than 1 km apart, for which purpose an optical data connection is particularly beneficial, in particular when making use of an Ethernet data connection.
For providing an underwater connection, wet-mateable connectors are known which can be mated underwater. Although such type of connectors is generally more complex than corresponding dry-mate connectors, which have to be mated above the water surface, wet-mateable connectors have several advantages. Components of the subsea installation can for example be disconnected and can be retrieved for servicing or exchange, additional components may be connected to an existing subsea installation, connections can be provided to a subsea structure after installation thereof on the ocean floor, and the like.
When establishing a connection subsea, a first connector part, for example a plug part, is engaged with a second connector part, for example a receptacle part. Due to the large water depth, this is generally done by making use of a remotely operated vehicle (ROV), which for example holds one connector part and engages it with the other connector part. During the engagement, friction between moving connector parts may generate microscopic particles that become immersed in a fluid filling a connector part. Such particle can settle on an optical contact of the connector part, thereby causing high optical losses upon full engagement of the first and second connector parts. This can result in a reduced performance of the connector or in total failure of the connector. To remove such failure, the connector needs to be brought up to the surface where it is replaced or serviced. This results in high costs (for example due to the enormous costs associated with operating an offshore vessel that is capable of performing such replacement) and further in a significant delay.
It is desirable to improve the reliability of the mating of such connectors in a subsea environment, and in particular to ensure that a connection having the desired performance can be established. It should be avoided that the connector needs to be brought up to the surface to establish a reliable connection. It is desirable to avoid a reduced quality of such connection in fiber optical connectors, which may be caused by particles or other impurities that have settled on the optical contact surfaces.